DOhC turbo VS 3800SC

[Fastback86]

Cool. What about the ring placement? Ryan was pointing out that on a lot of motors, the rings are close together and near the top of the piston to help with emissions, but that most pistons made for boost have the rings farther down away from the combustion.

[Series8217]

Cool. What about the ring placement? Ryan was pointing out that on a lot of motors, the rings are close together and near the top of the piston to help with emissions, but that most pistons made for boost have the rings farther down away from the combustion.

Yeah, the top ring is 1/4" to 1/3" from the top of the piston. It looks to me like breaking the ring lands on this thing would take a lot of effort.
Oh and I lied, I do have a set of rings sitting here. 1.5mm compression rings (both).

[Shaun41178(2)]

I will say this about the dohc and turbo at 10 psi. Remember folks 10 psi on one turbo is not the same as 10 psi on another.

Tim is running a decent sized turbo and has a good tune.

THE TUNE IS EVERYTHING WITH THAT MOTOR.

exclamation point.

WCF is running a tiny ass grand national turbo and a shitty ass tune. THey never dyno tuned it and use a turbo blowing a shitton of hot air at redline, combined with a shitty tune, blew head gaskets. So they o-ringed the heads or block whichever one to stop that from happening. I heard a story while at wheatstock of the WCF dohc turbo car getting beat by a 3500 lb grand prix with the S2 Superhcarged motor in it. Mods to the grand prix/ No clue, but the fiero was getting walked from a roll by a few cars. Thats very sad. There were Fieros with stock 3800 S/c swaps there faster then the WCF car. WHich proves that wcf has a shitty tune and a undersized turbo.

Its all in the tune. Internally stock b16 honda motors, designed for emissions and tight ring gaps from the factory can put out 300 whp on a completely stock bottom end and most of the time, stock heads too. Its all in the tune and properly sized turbo. They dont' blow ring lands when they are carefull and dont' push too hard. In fact most blow sleeves before the rings go.

Theory and real world can vary greatly. In theory based on numbers a top fuel dragster could never reach 300 mph in the qtr. This was proposed my mathemeticians way smarter then me. Well that didnt' quite work out now did it? They are hitting 325 mph now.

Hell Travis(1fst2m6) dropped a 125 shot on his car with other mods and layed down 280 whp. Thats 170 more hp then a stock fiero 2.8 puts down at the wheels. RIngs held up as far as I know. At least they didnt' blow the tops of the pistons off. Mine haven't blown the tops of the pistons off either and I have stock rings and pistons. 89k miles stock motor too.

Tune tune tune. is the key here people. As well as the use of the correct parts.

[The Dark Side of Will]

How advanced is the L36 chamber design? Is it stone age like the head material would suggest?

Even if the pistons can withstand this added pressure and heat, chances are the tightly-gapped piston rings cannot.

I knew there was something I was missing. Thanks for reminding me!
High mileage may be saving these engines from ugly deaths. Due to wear, the ring gaps open up over time. High mileage engines have wider ring gaps (and can therefore take more boost) than new, fresh, relatively low mileage L36's.

[The Dark Side of Will]

In the world of factory engines, where emissions standards need to be observed; pistons and rings are designed to keep as much combustion pressure from leaking as possible. To do this, the factory moved the top piston ring groove as close to the piston as possible; thus exposing it to greater pressure to improve it's sealing ability.

It is my understanding that the top ring is closer to the top of the piston so there is less unburned mixture trapped between the piston and the wall.

Yes, that's the reason. Reduction of the crevice volume created by the top ring land.

[Sinister Fiero]

Series8217 - any info you can find out on that WCF motor would be appreciated. Thanks for sharing what you have.

Shaun - 100% agree. 10psi on a 35mm turbo is going to be vasty different than the amount of air getting moved at 10psi on a 70mm turbo. Tuning has a ton to do with it as well. But, like I said before, I have seen engines fail that had perfect tuning, but failed because of weak parts or incorrect clearances for the application.

What I would like to see is what all of these 3.4 DOHC turbo cars are running. I am hearing a bunch of numbers getting thrown around about boost and HP claims, but like Shaun said, the WCF car got beat by a FWD 3800-powered W-body. Where are the 1/4 mile timeslips?

[The Dark Side of Will]

Here's a 7 psi 3.4 DOHC turbo dyno:
phpBB/viewtopic.php?t=843

[Aaron]

Here's a 7 psi 3.4 DOHC turbo dyno:
phpBB/viewtopic.php?t=843

That is Tim's car. He upgraded the tuning equipment, bumped boost to 10psi, did some tuning, and the results were staggering. Gained 60+ rwhp with 3psi. It is ALL about the tune.

[TurboGT]

Here is the 60* posting of his dyno

http://60degreev6.com/discussion/viewtopic.php?t=7529

If you go to this link he has his dyno graphs of that same car

[Pyrthian]

I will say this about the dohc and turbo at 10 psi. Remember folks 10 psi on one turbo is not the same as 10 psi on another.

yes yes. psi is pressure, not volume.
volume makes the HP's
just like a good intake will LOWER your boost, and yet you make more power.

[Sinister Fiero]

My boost gauge said 10 psi- data logs say 8 psi @ 4500 dropping to 7 @ redline (because of the MBC). The FTC was doing 1.5 degrees of timing retard. There's probably more power available by tuning ignition and upping the boost. I'm going to wait until I'm OBD2 to do that though.

Tim

:scratch:

So he doesn't even know how much boost he was running? What is right, the gauge or the logs?

Anyway, impressive dyno numbers if indeed they are his and they are factual. <-- I am sure some people on here are going to flame me for that comment but consider how many fabricated dyno and 1/4 mile claims have we seen in the past...

Nonetheless, I would like to see some 1/4 mile numbers. Dyno sheets are ok, but 1/4 mile timeslips tell the whole story.

Look, I'm not trying to be a dick here but I am in contact with several people running turbos on 3.4 DOHC engines and none of them seem to be making this kind of power. Furthermore, if it were "this easy" to get this kind of power out of a "stock" 3.4 DOHC engine "reliably", everybody would be doing it. So where are all the 3.4 DOHC turbo 1/4 times on the 1/4 mile list? :dontknow:

[The Dark Side of Will]

Why the heck does he want to convert to OBDII?

[The Dark Side of Will]

if it were "this easy" to get this kind of power out of a "stock" 3.4 DOHC engine "reliably", everybody would be doing it. So where are all the 3.4 DOHC turbo 1/4 times on the 1/4 mile list? :dontknow:

Who's "everybody"? All dozen people on the whole intarweb who have turbo'd TDC's?

[Sinister Fiero]

Who's "everybody"? All dozen people on the whole intarweb who have turbo'd TDC's?

Good question. I guess everybody would encompass anyone who wants 325hp and 350tq out of a "bone stock" 160,000+mi 3.4 DOHC.

[Aaron]

I sat there and watched the dyno pulls, at a highly reputable shop. http://www.dynopro.com They are the same shop that I ran my white Z34 at. Look, Tim is a smart guy, makes good money, and knows his way around cars. I DROVE THE DAMN THING. It is making every bit of 325whp.

Everyone isn't doing it becuase not everyone owns a 3.4. And those who do, in the W-body world, are too busy saving up for a L67 swap. And in the Fiero world, well, that is where most all of the turbo 3.4s are..

Why the heck does he want to convert to OBDII?

For a few reasons. First and foremost, in the 97 DOHC the ODBII controlled the 4T65e, not the 60e. Tim wants to use this as his current one, even after getting a professional rebuild, is starting to slip. Also, with his DHP tuner, he can tune it for the boost without having to worry about piggyback and jerry-rigged FMU's and such.[/url]

[crzyone]

Who's "everybody"? All dozen people on the whole intarweb who have turbo'd TDC's?

Good question. I guess everybody would encompass anyone who wants 325hp and 350tq out of a "bone stock" 160,000+mi 3.4 DOHC.

I guess people who are looking to make those power numbers swap in a 3800sc because its easier and cheaper to get those numbers. Not too many people are willing or capable of fabricating their own turbo swaps but are capable of bolting in a 3800sc and maybe a few bolt on mods. The 3800 has a reputation of being a stout motor and can easily handle those power numbers.

The 3.4dohc is still uncharted, nobody knows how much power it can handle before it fails because nobody has blown one up yet. The kid with the bad tune doesn't count.

Until there are a dozen people running 300hp+ turbo 3.4s reliably, people won't be rushing to throw a turbo on a 3.4dohc as a daily driver.

I believe WCF and Matt hawkins are both using old GN turbos on their 3.4s, not exactly the most efficient turbo for a high flowing engine like the 3.4. Both swaps would be making way more power with a properly sized efficient turbo.

[The Dark Side of Will]

Why the heck does he want to convert to OBDII?

For a few reasons. First and foremost, in the 97 DOHC the ODBII controlled the 4T65e, not the 60e. Tim wants to use this as his current one, even after getting a professional rebuild, is starting to slip. Also, with his DHP tuner, he can tune it for the boost without having to worry about piggyback and jerry-rigged FMU's and such.[/url]

4T60E = vacuum modulator, 4T65E = pressure control solenoid
I guess that's almost a good enough reason. Probably be cheaper in the long run to buy a stand alone trans controller, though.

OBDI can be tune on the fly without bandaids, as well.

[crzyone]

Use a paddle shifter to control it like Whipped.

[Shaun41178(2)]

I believe WCF and Matt hawkins are both using old GN turbos on their 3.4s, not exactly the most efficient turbo for a high flowing engine like the 3.4. Both swaps would be making way more power with a properly sized efficient turbo.

Matt Hawkins is running a 46 trim T4 wheel in a modified T3 compressor housing. WCF and Kameo kid use the GN turbo.

And yes with a better turbo(read larger) I really think the motor can do 400 crank. With a Gt35R I bet it can do 350 whp on 10 psi on a good tune.

[Aaron]

Tim is using a T04-60e..

350whp easy on a GT35r. Those things run at like 81% adiabatic efficency :salute: